剑指Offer面试题30包含min函数的栈java版

题目：定义栈的数据结构，请在该类型中实现一个能够得到栈最小元素的min函数。
分析：采用辅助栈

import java.util.Stack;
import java.util.*;
public class Solution {
    Stack<Integer> data = new Stack<Integer>();
    Stack<Integer> minstack = new Stack<Integer>();
    int min = Integer.MAX_VALUE;
    public void push(int node) {
        data.push(node);
        if(minstack.isEmpty()||node<minstack.peek()){minstack.push(node);}
        else{minstack.push(minstack.peek());}
    }

    public void pop() {
        if(!minstack.isEmpty()&&!data.isEmpty()){data.pop();minstack.pop();}

    }

    public int top() {
        return minstack.peek();
    }

    public int min() {
        return minstack.peek();
    }

}